This change introduces a strategy for expanding a URI template into a
URI and makes it a property of the RestTemplate and AsyncRestTemplate
so that they can be pre-configured with such a strategy.

The DefaultUriTemplateHandler relies on UriComponentsBuilder internally
and provides functionality equivalent to using the UriTemplate.
A DefaultUriTemplateHandler can also be configured to parse the path
of a URI template into path segments in order to allow expanding URI
variables according to path segment encoding rules.

Issue: SPR-12750